Vehicle stopping control system



Jan. 10, 1967 R. E. ARCHIBALD VEHICLE STOPPING CONTROL SYSTM Filed AMay 27, 1964 United States Patent hce Signal Corporation, Rochester, N.Y., a corporation of New York Filed May 27, 1964, Ser. No. 370,734 7 Claims. (Cl. 246-122) Generally speaking, the present invention relates to vehicle control systems, and more particularly pertains to a system for controlling a vehicle to stop with a predetermined point on the vehicle coming to rest adjacent a predetermined wayside point.

During the control of vehicles such as subway trains or the like, it is often desirable to be able to stop the vehicle in such manner that it comes to rest with a predetermined vehicle point (such as a particular chosen car of the train) adjacent a predetermined point along the station platform, so as to provide for maximum passenger convenience and safety while they are loading and unloading at the station. For example, under normal circumstances it would ordinarily be desirable to stop the subway train with the center of the train substantially at the center of the station platform. However, it should be understood at this time that the system of the present invention is equally applicable for providing such stop control of vehicle types other than the subway trains mentioned above and at other types of wayside locations, wherever it is desired to stop a vehicle with some chosen point on the vehicle coming to rest substantially at a predetermined wayside point.

Accordingly, a general object of the present invention is to provide a stopping control system whereby a vehicle can be brought to a stop with a predetermined point on the vehicle adjacent a predetermined point on the wayside. 1

A more specic object of the present invention is to provide a control system effective to stop a railway vehicle, such as a subway train, with the center of the vehicle at the center of a station platform.

A still further object of the present invention is to provide a stop control system whereby the brakes on a subway train are automatically applied so as to properly bring the train to a stop with a predetermined point on the train adjacent a predetermined wayside point ata subway platform.

Other objects, purposes and characteristic features of the present invention will be in part pointed out as the description of the invention progresses, and in part obvious from the accompanying drawings, in which:

FIG. 1 is a simplified diagrammatic illustration showing a typical station platform location and an approaching train, each equipped in accordance with one embodiment of the present invention; and

FIG. 2 shows in more detail the train carried apparatus provided in accordance with this same embodiment of the present invention.

With reference to FIG. 1, a stretch of track is illustrated adjacent a station (or subway) platform SP at which the approaching train T (assumed to be travelling from left to right in FIG. 1 as indicated by the dotted arrow) is desired to be stopped, for example, to permit loading and unloading of passengers. In the illustrated embodiment of the present invention, it will be assumed for descriptive purposes that this approaching train T is desired to be stopped with its center coming to rest substantially at the center of the station platform SP. In FIG. l it will be noted that the center of this station platform SP is marked by an inert, tuned Wayside loop WL, for purposes to be described hereinafter.

Generally speaking, the approaching train T is assumed to be equipped in accordance with the present invention Patented Jan. 10, 1967 and carries a receiver coil RC disposed on the train in such manner that it inductively cooperates with the tuned wayside loop WL to effect operation of the train carried apparatus (shown more particularly in FIG. 2 of the accompanying drawings) to indicate or register when the head-end (right-hand end) of the train T passes the center of the station platform SP. In the illustrated embodiment of the present invention, it has been assumed that the train T is, for example, a passenger carrying subway vehicle made up of a plurality of cars and having a total length designated by the reference character L in the accompanying drawings.

Referring now to FIG. 2 and the train carried apparatus, the approaching train T is more particularly provided with an AXLE-DRIVEN FREQUENCY GENERATOR 10 of the type well-known in the art effective to produce an output frequency which varies in proportion to, or is the analog of, the actual speed at which the train is travelling. This actual speed analog signal is applied over line l1 to a FREQUENCY TO D.C. VOLTAGE CONVERTER circuit 12 effective to produce at its output (wire 13) a D.C. voltage whose magnitude is at all times proportional to or the analog of the actual speed of train T.

The vehicle carried receiver coil RC, disposed so as to mark the head-end of the approaching train T, is connected at the input of a suitable RECEIVER circuit 14 of a well-known type effective to cause the receiver output relay RCR to become picked up upon passage of the head-end of the train T at the center of the station platform SP; i.e. upon passage of the train carried receiver coil RC at the tuned wayside loop WL. This relay RCR is made suiiiciently slow releasing, after once being picked up, so that it will remain in its picked up position (with its front contact I5 closed) at least until the train T is thereafter brought to a stop, as will be described.

In accordance with the closing of front contact 15 of relay RCR, as the train carried receiver coil RC passes the wayside loop WL, the D.C. voltage output from converter circuit l2 is coupled as input to a suitable IN- TEGRATING CIRCUIT I6 effective to provide continual integration of the D.C. voltage supplied thereto and to thereby produce at its output, on wire 17, a voltage sign'al which varies proportionalely with, or is the analog of, the actual distance that the receiver coil RC (headend of the train T) has travelled since passing the wayside loop WL (center of the station platform SP). This actual distance analog signal is supplied as an input to a suitable SIGN CHANGE circuit I8 with the effect that, at the output thereof on wire 19, a negative polarity signal is produced in proportion to the actual distance thatthe front end of the vehicle is beyond the center of the station platform.

Also provided on the train T is a suitable potentiometer, including resistor 20, whose movable arm 21 is assumed to be set, in accordance with the illustrated embodiment of the present invention, to pick off a predetermined voltage signal proportional to or the analog of onehalf the known train length L.

This voltage analog of one-half the known train length (at movable arm 21), together with the negative voltage analog of the actual distance travelled (on wire 19), are supplied as inputs to a suitable ADD circuit 22 to thereby produce at output wire 23 a signal proportional to the difference between the two input signals from wires 19 and 21 respectively. That is, the signal produced at the output wire 23 decreases proportionately as the actual distance travelled by the headend of the train T, after passing the center of the station platform SP, increases towards a distance value equal to one-half of the known train length. This difference signal from ADD circuit 22 is supplied to the right-hand winding 24 of a suitable differential relay DR which, in turn, is utilized to automatically control brake application aboard train T, in a manner to be described in more detail hereinafter.

Connected to the left-hand winding 25 of the differential relay DR, is the voltage signal picked off a potentiometer comprising resistor 26 and movable arm 27. With reference to FIG. 2, it should be noted that this movable potentiometer arm 27 is adjusted to pick off a predetermined voltage signal Value proportional to any known distance required for the train T to come to rest from its existing speed, after having its brakes applied.

The differential relay DR is thus supplied with these two inputs at its respective windings 24 and 25, and controls its operating contact 28 in such a manner that the contact remains closed (as shown) as long as the difference signal supplied to the right-hand winding 24 is larger than the signal applied to theleft-hand winding 2S; i.e; until the head-end of the train T has travelled past the center of the platform SP by a distance equal to half the trains length less the distance required by the vehicle to stop after having its -brake applied. This contact 28 controls the energization of brake control wire 29 leading to and controlling the train braking apparatus (not shown) in such a manner that deenergization of wire 29 (contact 28 opened) causes automatic application of such brakes.

In order to point out in more detail how the system of this invention operates, it will now be assumed that the train T is approaching the station platform SP from left to right as viewed in FIG. l at some predetermined normal approach speed which might be called for, for example, by information communicated from the wayside to the vehicle via conventional coded track circuitry (not shown) and effective to control the vehicle to operate at the desired approach speed, either through the use of conventional cab signaling, train control and/or completely automatic train operating apparatus if the vehicle is unmanned. The workings of such apparatus whereby the trains speed can be kept substantially constant is well-known to those skilled in the art.

Accordingly, when the head-end of this train T passes the wayside loop WL, the relay RCR becomes picked up, as prevously described, to connect the voltage analog of actual train speed (from converter circuitry 12) to the input of the integrating circuitry 16. As mentioned previously, this integrator 16 produces an output signal on wire 17 which is at all times proportional to the distance that the head-end of the train T (as marked by coil RC) has travelled since passing the center of the station platform SP (as marked by loop WL).

Subsequent to the sign changing operation at circuit 18, the negative analog of this actual distance travelled by the head-end (on wire 19) is compared, at ADD circuit 22, to the analog (on wire 21) proportional to onehalf the known train length L, and, the output of this ADD circuit 22 is an error signal which gradually decreases in magnitude as the actual distance travelled increases towards this desired distance value equal in the illustrated embodiment to one-half the trains length. The right-hand winding 24 of the differential relay DR is thus supplied with a decreasing energizing signal, and, when such signal finally decreases to that value supplied to the left-hand winding 25, the operating contact 28 is opened to deenergize the brake control wire 29 and cause initiation of an automatic brake application aboard the vehicle. As pointed out previously, the potentiometer arm 27 is adjusted so that this brake application, now in force, will cause the train T (which may be either manned or unmanned) to stop with its center resting substantially at the middle or center of the station platform SP.

In view of the above discussion, it should be obvious that various modifications and/or -adaptations may the spirit or scope of the invention. For example, the system of the present invention is highly flexible in that the wayside loop WL and the train carried receiver coil RC can be disposed at any desired wayside and vehicle points respectively, with potentiometer adjusted Iaccordingly so that any desired point on the train T (behind the location of coil RC) can be stopped accurately at a given point along the station platform SP. Thus,

the system of the present invention might well be utilized be applied to the present invention, vto meet with the various requirements of practice, without departing from for controlling the train T to stop with some special car, for example, (not necessarily at the center of the train) positioned at Iany desired point along the station platform SP.

In the foregoing discussion of the illustrated embodiment of the present invention, it was assumed that the potentiometer 26-27 was provided to produce a voltage signal which takes into account any distance require-d by the vehicle to stop after its brakes are applied. However, it should be obvious that, if the vehicle does not require any appreciable distance to stop after its brakes are applied, the control provided by such potentiometer could 'be completely omitted and the vehicle brakes applied when the output of the ADD circuit 22 decreases substantially to zero.

Furthermore, it should be also understood that the differential relay DR employed in the illustrated embodiment of the present invention to operate contact 28 in 'accordance with ythe difference between the signals on potentiometer arm 27 and wire 23 respectively, has been selected to perform this function merely for the purpose of disclosure, and, that any other suitable form of differential circuit means could be employed in its stead to initiate brake application when the vehicle is detected as having travelled its proper distance. Similarly, the ADD circuit 22, together with the SIGN CHANGE circuit 18, could readily be replaced by a single difference amplifier circuit well-known in the art and capable of producing the desired signal representative of the difference between the actual and desired distances that the head-end of the vehicle has travelled, after passing the center of the station platform SP.

Accordingly, in preference to merely controlling the vehicle brakes on or off, as assumed in the drawings, the train approaching the station platform SP could also be controlled, if desired, to have its throttle automatically `adjusted in accordance with the distance that the headend has travelled since passing the center of the station platform, as well as being controlled to varying degrees of braking, so as to possibly attain smoother deceleration. Thus, the train control organization provided by the present invention might be utilized to produce a desired speed signal (for example, some functions of the output of the AD-D circuit 22) which varies in accordance with a predetermined desired pattern for vehicle speed adjacent the stopping location and w-hich could then lbe compared to the actual speed output from the AXLE-DRIVEN FREQUENCY GENERATOR 10, so that the throttle and brakes might be adjusted accordingly to produce varying degrees of stopping effort on the vehicle necessary to cause it to conform to the desired speed pattern as the head-end of such vehicle approaches its desired stopping location.

Having thus described a vehicle stopping control system as one particular embodiment of the present invention, it is to be understood at this time that various other modifications, adaptations and alterations may be applied to the specific form shown to meet the requirements of practice without in any manner departing from the spirit or scope of the present invention.

What I claim is:

1. In a system for controlling a vehicle to stop with a first predetermined point on said vehicle adjacent a predetermined Wayside point, the combination of,

(a) first signal producing means effective to provide a first signal proportional to the known dist-ance exist-2 ing between said first predetermined vehicle point and a second predetermined point located on said vehicle forward of said first predetermined point in the direction of vehicle travel,

(b) second signal producing means rendered effective upon passage of said second predetermined vehicle point `at said wayside point to thereafter provide a second signal proportional to the distance that said second point has travelled past said wayside point,

(c) means responsive to said first and second signals effective to produce a third signal indicative of the difference between said first and second signals, and

(d) control means responsible to said third signal effective to initiate a stopping of said vehicle when said third signal decreases below a predetermined value.

2. The vehicle control system specified in claim 1 wherein said vehicle is equipped with braking means effective when applied to cause a stopping of said vehicle, said braking means requiring a predetermined stopping distance to completely stop said vehicle after being applied, and wherein said control means -includes *brake applying means effective to cause application of said vehicle braking means when said third signal decreases below a value proportional .to said predetermined required stopping distance.

3. `In a system for controlling a vehicle to stop with a first predetermined point on said vehicle adjacent a predetermined wayside point, the combination of,

(a) means for producing a signal proportional to the actual speed of said vehicle,

(b) integrating means responsive to the passage of a second predetermined point on said vehicle at said predetermined wayside point for thereafter integrating said speed signal to produce a distance signal proportional to the actual distance that said second predetermined vehicle point is beyond said wayside point, said second predetermined vehicle point being located forward of said first predetermined vehicle point by a predetermined distance in the direction of vehicle travel, and

(c) means responsive to said distance signal effective to initiate the stopping of said vehicle when said actual distance is substantially equal to said predetermined distance.

4. In vehicle control system, apparatus for detecting when a first predetermined point on said vehicle is substantially adjacent a predetermined wayside point, said apparatus comprising in combination,

(a) first signal producing means effective to provide a first signal proportional to the known -distance existing between said first predetermined vehicle point and a second predetermined point located on said vehicle forward of said first predetermined point in the direction of vehicle travel,

(b) second signal producing means rendered effective upon passage lof said second predetermined vehicle point at said wayside point to thereafter provide a second signal proportional to the distance that said second point has travelled past said wayside point, and

(c) means responsive to saidtrst and second signals effective to register when the difference between said first and second signals decreases below a predetermined value.

5. In a system for centering vehicles at a station platform, the combination of,

(a) means responsive to the passage of the head-end of a vehicle at the center of said station platform to thereafter provide a registration of the actual distance 6 that said head-end is beyond the center of said station platform, and (b) means responsive to said actual distance and to the known distance on said vehicle from the head-end 5 thereof to the middle of said vehicle for initiating the stopping of said vehicle when said actual distance has increased substantially into agreement with said -known distance. 6. In a system for centering a predetermined point on 10 a vehicle at a station platform, the combination of,

(a) speed responsive means effective to produce an output signal which varies in proportion to the actual speed of a vehicle adjacent said platform,

(b) integrating means rendered effective when the head-end of said vehicle passes the center of said station platform -to thereafter provide integration of the output signal from said speed responsive means to thereafter produce an output signal which varies in proportion to the actual distance that the head-end has travelled since passing the center of said station platform,

(c) distance registering means effective to produce an output signal proportional to the known distance existing between the headend of said vehicle and the predetermined point on said vehicle desired to be stopped adjacent the center of said station platform, and

(d) means responsive to the output signals from said integrating means and said distance registering means effective to initiate a stopping of said vehicle when said actual distance has increased substantially into agreement with said known distance.

7. In a system for controlling the stopping of a vehicle equipped with braking means adjacent a predetermined stopping area, the combination of,

(a) means partly on the vehicle and partly on the wayside effective to register when the head-end of the vehicle passes the center of la predetermined stopping area,

(b) first signal producing means effective to produce a first output signal proportional to the known distance existing between the head-end of said vehicle and the center of said vehicle,

(c) second signal producing means effective to produce an output signal proportional to the actual vehicle speed,

(d) integrating means responsive to said head-end registering means and the output of said second signal producing means rendered effective when the headend of the vehicle passes the center of the stopping area lto thereafter integrate said second signal to produce -a third signal proportional to the actual distance that the vehicle head-end is beyond the center of the stopping area,

(e) comparing means responsive to said first and third signals effective to produce a difference signal proportional to the difference between the actual distance that the head-end has travelled past the center of the stopping area and the known distance from the vehicle head-end to the vehicle center, and

(f) brake applying means responsive to said difference signal rendered effective to initiate an application of said vehicle braking means when said difference signal reduces to a predetermined value.

No references cited.

ARTHUR L. LA POINT, Primary Examiner.

S. B. GREEN, Assistant Examiner. 

1. IN A SYSTEM FOR CONTROLLING A VEHICLE TO STOP WITH A FIRST PREDETERMINED POINT ON SAID VEHICLE ADJACENT A PREDETERMINED WAYSIDE POINT, THE COMBINATION OF, (A) FIRST SIGNAL PRODUCING MEANS EFFECTIVE TO PROVIDE A FIRST SIGNAL PROPORTIONAL TO THE KNOWN DISTANCE EXISTING BETWEEN SAID FIRST PREDETERMINED VEHICLE POINT AND A SECOND PREDETERMINED POINT LOCATED ON SAID VEHICLE FORWARD OF SAID FIRST PREDETERMINED POINT IN THE DIRECTION OF VEHICLE TRAVEL, (B) SECOND SIGNAL PRODUCING MEANS RENDERED EFFECTIVE UPON PASSAGE OF SAID SECOND PREDETERMINED VEHICLE POINT AT SAID WAYSIDE POINT TO THEREAFTER PROVIDE A SECOND SIGNAL PROPORTIONAL TO THE DISTANCE THAT SAID SECOND POINT HAS TRAVELLED PAST SAID WAYSIDE POINT, (C) MEANS RESPONSIVE TO SAID FIRST AND SECOND SIGNALS EFFECTIVE TO PRODUCE A THIRD SIGNAL INDICATIVE OF THE DIFFERENCE BETWEEN SAID FIRST AND SECOND SIGNALS, AND (D) CONTROL MEANS RESPONSIBLE TO SAID THIRD SIGNAL EFFECTIVE TO INITIATE A STOPPING OF SAID VEHICLE WHEN SAID THIRD SIGNAL DECREASES BELOW A PREDETERMINED VALUE. 